This invention relates to a method and means for pumping gas lasers and more particularly to high-power gas lasers which are pumped by ion beams.
It is well known in the prior art that lasers of various types are in use and experimentation of new types are always under study. Such lasers include solid state, chemical and gaseous types. These laser types are pumped by intense light sources, other lasers, nuclear fission reactors, electron beams, and electric discharges. In another type of prior art laser, an ion beam is passed through a thin foil or sheet of material in order to make charge-exchange collisions and produce an inverted population of a lasing species.
Heretofore relativistic electron beams have been successfully applied to the excitation of high pressure gas lasers including XeF, HgCl, He.sub.2.sup.+ --N.sub.2 .fwdarw.N.sub.2.sup.+ (B.fwdarw.X), Ar--N.sub.2, XeCl, and those type of lasers which are known as excimer lasers (e.g., xenon), energy transfer lasers (e.g., argon-nitrogen), carbon dioxide lasers, and other lasers which are commonly referred to as the rare-gas-halides (e.g. krypton fluoride and xenon fluoride) and the group-six lasers. For example, several rare gas halogen species have heretofore been made to lase by pumping with an electron beam. These lasers produce pulses of relatively short duration, typically submicrosecond. In these prior art gas laser systems, a rare gas, e.g. argon, has been used as diluent. After initial ionization of the gas mixture, processes result which lead to a population inversion of the desired excited state species.
In the typical prior-art gas laser, a pulsed beam of electrons of 0.1 to 10 MeV energy and 50-100 nanosecond duration, produced in a diode, is passed through a metallic foil, e.g. 25 .mu.m thick titanium, into a chamber filled with a high-pressure (1-10 atm) gas mixture. The optical axis of the laser is typically transverse to the direction in which the electron beam is injected into the gas cell. The efficiency, defined as the ratio of the output light energy to the electron energy deposited in the gas cell, has been found to be a few percent or less for these lasers.